This invention is related to a tape loading mechanism for a VCR(Video Cassette Tape Recorder)deck, particularly for a deck having two cams which drive a pinch roller and take up roller independently thereby resulting in moving each driving parts in sequence and allowing the tape to take the most optimum path and making the construction thinner.
As shown in FIG. 1, in the prior art VCR deck tape loading mechanism design, head drum(H) is placed inclined in the central part of the rear section of main base 1 and a cassette c is mounted in forward section of the main base 1 in which are contained respectively supply reel 20 on the left and take up reel 21 on the right.
Loading gears 24,25 meshing each other are provided under the head drum(H).
Loading levers 26,27 each having two levers and positioned above the loading gear 24,25 are connected to the loading gears 24,25 respectively, and, in turn, the loading levers 26,27 are connected to slant bases 1,2 respectively, thereby each slant base moves from inside of the mouth M of tape cassette to the position of loading completion in response to the rotation of the loading gears 24,25, and moves further until it comes to compress against V-stopper(not shown) upon further rotation of the loading gears.
There are provided on the main deck D, a loading motor 3 at the right corner of the rear section, a cam gear 12 in front of the loading motor, a capstan motor 23 between them, and a gear train G i.e., gears a 5, b 6, c 7 and d 8 which transmit power via a worm 4 from the loading motor 3 to the cam gear 12 on one side of the capstan motor 23.
Between the capstan motor 23 driving gear 28 and the loading gear 25, there is provided a relay lever 14 which is adapted to move in straight line in order to connect or disconnect power selectively, a pin 14a fixed at one end of the relay lever 14 and moving inside of a cam groove 12a of the cam gear 12 in response to the rotation of the cam gear 12 enabling the straight line movement and a relay gear 13 on the rear end of the relay lever 14 to connect or disconnect above capstan motor 23 driving gear 28 to the loading gear 25.
A reel ratchet 22 is movably connected by a shaft 22' and a pin 22a in one end of the ratchet is inserted in a cam groove 12a of the cam gear, so that the reel ratchet moves in response to the rotation of the cam gear 12.
A pinch arm 10 having a pinch roller 30 and a pinch lever 9 are connected by the same shaft 10' on one side of the cam gear 12, a torsion spring is placed on the shaft 10' while both ends of which are latched on a latching tips 9a, 10a of pinch lever 9 and pinch arm 10 respectively so as to keep pushing both parts close together, one side of the pinch lever 9 contacts with the cam pin 17 fixed on the upper surface of the cam gear 12, and the pinch arm 10 is connected with a tension spring 32 tending to rotate the pinch arm 10 in counter clockwise direction.
On one side of the pinch arm 10, a take up arm 11 having a guide roller 33 in the middle, is connected to a shaft 11', the shaft 11' is provided with a torsion spring 31 tending to rotate the take up arm 11 in clockwise direction, and a driving pin 34 projected upward and positioned in the middle of the loading lever 27 drives the rear 11a of the take up arm 11 forward when the slant base 2 is in loading condition.
In such a conventional mechanism, as shown in FIG. 2A, the pinch roller 30 and guide roller 33 are positioned in tape mouth M by the tension spring 32 biased on pinch arm 10 in unloaded condition.
On starting of loading in this condition, the driving motor 3 drives loading gear 24 and cam gear 12 through gear train G, as shown in FIG. 2B, the slant base 2 moves along the guide rail of main base 1 in response to the rotation of loading gear 25 and the driving pin 34 connected with slant base 2 through loading lever 27 rotates take up arm 11. Then the shaft 30' of pinch roller 30 in contact with take up arm 11 rotates pinch arm 10 so that the pinch roller 30 approaches to capstan shaft 23'. Also the cam gear 12 rotates making the cam pin 17 approach pinch lever 9.
In this condition, upon further rotation of cam gear 12, cam pin 17 further pushes pinch lever 9 so as to rotate pinch arm 10 biased by torsion spring 31 further, making the pinch roller 30 to contact closer with the capstan shaft 23' as shown is FIG. 2C.
As seen above, in the conventional mechanism, the driving guide parts are driven by one cam gear and can not be driven independently from each other. The achievement of the optimization of the tape path is difficult because the driving guide parts can not be driven on desired timing during loading.